I read about the kindle changes, and there are YT videos of how people are trying to avoid the books disappearing. I have not had any of my books disappear, and I am not sure what the whole thing even means. In any case, there are authors that i follow on Amazon, and I check their pages to see when they have one of their ebooks on sale, and if it is one i want to read, then i get it.
Many of the books are on Kindle Unlimited, and even if i have not found them on the sale price, I have them in my library, because you can keep the KU books as long as you want to.
I used to read them on my kindle, which was one of the 7” ones, lightweight and easy to hold and read as long as there are not charts or graphics.
Then, I started using my IPad Mini, which is more the size of an 8” kindle, but lighter weight. I like how easy it is to find new books and to close ones I have read with the iPad, so I do not even have a kindle anymore, and just use the Mini.
If I am reading a book that has pictures or charts, I use the larger iPad, because it is easier to see charts on that than it is on the Mini.
All of my kindle books are on all of my devices, so i can read from any one that i choose to use, including my iPhone, and I think that you can have the kindle app on almost any computer or tablet nowadays. I definitely recommend having a smaller size tablet of whatever make you prefer, and use that for reading. It does not have to be an actual Kindle.